Re: Do I need a switch with VLAN and QoS?

Discussion in 'Cisco' started by Stephen, Jun 16, 2009.

  1. Stephen

    Stephen Guest

    On Mon, 15 Jun 2009 14:55:44 -0700, "just bob" <kilbyfan@aoldotcom>
    wrote:

    >I think I finally need a real managed switch with VLAN and QoS. I need to
    >somehow prioritize VoIP traffic on a LAN.
    >
    >Basically San Francisco and Los Angeles Springs each have an Avaya IP Office
    >PBX which transfers calls over VoIP. We have no VoIP phones or other
    >devices, just these PBX's supporting VoIP to each other.
    >

    QoS only has an effect when you have congestion.

    If the PBX local interfaces are on their own LAN interfaces, then the
    traffic level will be sub 100 Kbps per active call - so room for 1000
    calls on a 100 Mbps port......

    >Previously these locations were connected via a Point-to-Point circuit with
    >gobs of extra bandwidth, and at my busy SF location I had the PBX on a sub
    >network away from all other traffic. But that is going away so now we need
    >to prioritize the local traffic. The new MPLS circuit will prioritize across
    >the WAN but locally I need to do something, too.
    >

    The main thing is to make sure the way you mark your traffic is
    compatible with the MPLS service (and that you have those MPLS options
    in your service, that they are turned on and working).

    >Let me know if you have any ideas. I'm hoping a very inexpensive switch with
    >basic management will do this for me.
    >

    This implies your MPLS access link is Ethernet based?

    you havent really given enough detail for any of us to suggest a "fire
    and forget" network design.

    A lot will depend on what kind of MPLS service you have, the QoS you
    get, your traffic profile and so on.

    I suspect a layer 3 switch that can remark the traffic going into the
    WAN is a good starting point if your existing equipment cannot handle
    that - but there are limitations

    also note if you have a "rate limited" WAN interface feeding into the
    MPLS (say a 10 Mbps pipe, but you can only use 4 Mbps), then most
    switches cannot combine QoS prioritisation and rate limiting on the
    same port - for that you may need a router.

    I like Cat 3560s / 3750s which are pretty flexible - but they do not
    have resilience options such as dual power feeds......

    They can rate limit is 10% port speed steps and still do QoS within
    that.

    >Thanks!
    >

    --
    Regards

    - replace xyz with ntl
     
    Stephen, Jun 16, 2009
    #1
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  2. Stephen

    Guest

    On Jun 16, 3:53 pm, Stephen <> wrote:
    > On Mon, 15 Jun 2009 14:55:44 -0700, "just bob" <kilbyfan@aoldotcom>
    > wrote:
    >
    > >I think I finally need a real managed switch with VLAN and QoS. I need to
    > >somehow prioritize VoIP traffic on a LAN.

    >
    > >Basically San Francisco and Los Angeles Springs each have an Avaya IP Office
    > >PBX which transfers calls over VoIP. We have no VoIP phones or other
    > >devices, just these PBX's supporting VoIP to each other.

    >
    > QoS only has an effect when you have congestion.
    >
    > If the PBX local interfaces are on their own LAN interfaces, then the
    > traffic level will be sub 100 Kbps per active call - so room for 1000
    > calls on a 100 Mbps port......
    >
    > >Previously these locations were connected via a Point-to-Point circuit with
    > >gobs of extra bandwidth, and at my busy SF location I had the PBX on a sub
    > >network away from all other traffic. But that is going away so now we need
    > >to prioritize the local traffic. The new MPLS circuit will prioritize across
    > >the WAN but locally I need to do something, too.

    >
    > The main thing is to make sure the way you mark your traffic is
    > compatible with the MPLS service (and that you have those MPLS options
    > in your service, that they are turned on and working).
    >
    > >Let me know if you have any ideas. I'm hoping a very inexpensive switch with
    > >basic management will do this for me.

    >
    > This implies your MPLS access link is Ethernet based?
    >
    > you havent really given enough detail for any of us to suggest a "fire
    > and forget" network design.
    >
    > A lot will depend on what kind of MPLS service you have, the QoS you
    > get, your traffic profile and so on.
    >
    > I suspect a layer 3 switch that can remark the traffic going into the
    > WAN is a good starting point if your existing equipment cannot handle
    > that - but there are limitations
    >
    > also note if you have a "rate limited" WAN interface feeding into the
    > MPLS (say a 10 Mbps pipe, but you can only use 4 Mbps), then most
    > switches cannot combine QoS prioritisation and rate limiting on the
    > same port - for that you may need a router.
    >
    > I like Cat 3560s / 3750s which are pretty flexible - but they do not
    > have resilience options such as dual power feeds......
    >
    > They can rate limit is 10% port speed steps and still do QoS within
    > that.
    >
    > >Thanks!

    >
    > --
    > Regards
    >
    > - replace xyz with ntl


    Incidentally, I am using Catalyst 3750 switches in conjunction with
    external RPS (RPS 675) which can act as a redundant power supply if
    you were to lose a Power supply on one switch.
     
    , Jun 18, 2009
    #2
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  3. "" <> writes:
    >Incidentally, I am using Catalyst 3750 switches in conjunction with
    >external RPS (RPS 675) which can act as a redundant power supply if
    >you were to lose a Power supply on one switch.


    And then if you do lose external power, you have to reboot the switch
    to get back your power redundancy. Whee... (can you tell I'm not
    a big fan of the Cisco RPS solutions?).

    Why cisco doesn't make a true dual power switch in that product level
    is still a total mystery, other than pushing that class of users up to
    the very expensive next line of switches that do.
     
    Doug McIntyre, Jun 18, 2009
    #3
  4. Stephen

    Thrill5 Guest

    I am also not a fan of Cisco's RPS solution for the same reasons plus a few
    more. The current solution just isn't workable in because of the reboot
    issue. We used to install RPS's in all our closets that we put in 3750's
    but not anymore. The reboot issue to get power to switch back was a real
    problem. I think you can switch it back without a reboot, but you need to
    push some buttons on the RPS to do it, and that's impossible at remote
    sites. We had one location that had a bad power circuit and the thing would
    switch over the RPS every time. We would then need to schedule a reboot of
    the switch in the evening. The other problem is that sometimes the WAN
    router would also go down during the power blip and the SNMP trap from the
    switch wouldn't make it to the NMS. The device should send the the trap
    that it's on the RPS every 10 minutes to ensure that the trap is received.
    After having this problem all the time, the NOC finally said enough and we
    stopped deploying them and removed them from most locations.

    The othe problem is that RPS's aren't managable, you should be able to get
    the status of the RPS via the devices its attached to. It should also be
    able to power more than one device if the sum of power requirements of the
    requested devices is less than it's total output. We all know that Cisco
    doesn't want to be in the RPS business, so why not publish a spec and let
    others develop them? A great solution would have the following specs:

    Intelligent interface between the RPS and the device it's attached to. A
    simple inexpensive interface would have the existing power connections, with
    an integrated USB, so that the RPS and the device could each exchange
    capabilities and status.

    The RPS is also a UPS, with battery backup. This could be the way that
    Cisco encourages other vendors to supply products, namely UPS vendors.
    Cisco could develop a proprietary RPS interface and then license it to UPS
    vendors. The UPS vendors could then sell a plethora of solutions with
    different numbers of power interfaces, total output power, and battery
    times. A great solution for Cisco AND its customers. I would pay a premium
    for this product because now you could not only have redundant power, but
    also backup power, and you could size the system to meet the specific needs
    of each location. The current one-size-fits-all solution is too expensive
    and not flexible enough and much to clunky to deploy on a large scale.


    "Doug McIntyre" <> wrote in message
    news:4a3a9986$0$92360$...
    > "" <> writes:
    >>Incidentally, I am using Catalyst 3750 switches in conjunction with
    >>external RPS (RPS 675) which can act as a redundant power supply if
    >>you were to lose a Power supply on one switch.

    >
    > And then if you do lose external power, you have to reboot the switch
    > to get back your power redundancy. Whee... (can you tell I'm not
    > a big fan of the Cisco RPS solutions?).
    >
    > Why cisco doesn't make a true dual power switch in that product level
    > is still a total mystery, other than pushing that class of users up to
    > the very expensive next line of switches that do.
     
    Thrill5, Jun 19, 2009
    #4
  5. Stephen

    bod43 Guest

    On 19 June, 00:20, "Thrill5" <> wrote:

    I think that he docs say that the switch *may* reboot when
    switching back (via) the front panel.

    I believe that the RPS for the 3750-E is remotely managable.
    I know its different 'cos some bright spark ordered these
    for some 3750's. Has more pins on connector.

    BTW - I don't like the solution either. I fail to see how it
    will actually help uptime. Maybe if you had flaky power?
    In the UK mains power is *very* reliable.
     
    bod43, Jun 19, 2009
    #5
  6. Stephen

    Thrill5 Guest

    The RPS is only a redundant power supply, just in case the internal power
    supply fails. With the blinders on, that is the product that Cisco
    developed. A system with built-in redundant power supplies doesn't have the
    same limitations. For example, a 6500 with redundant power supplies can be
    connected to two different circuits, and one of them can be connected to a
    UPS. If either side fails, the other can take over, and they automatically
    switch back and forth. You can easily switch over to an RPS, but it's not
    easy to switch back which is its achilles heel.

    "bod43" <> wrote in message
    news:...
    > On 19 June, 00:20, "Thrill5" <> wrote:
    >
    > I think that he docs say that the switch *may* reboot when
    > switching back (via) the front panel.
    >
    > I believe that the RPS for the 3750-E is remotely managable.
    > I know its different 'cos some bright spark ordered these
    > for some 3750's. Has more pins on connector.
    >
    > BTW - I don't like the solution either. I fail to see how it
    > will actually help uptime. Maybe if you had flaky power?
    > In the UK mains power is *very* reliable.
    >
    >
    >
     
    Thrill5, Jun 19, 2009
    #6
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